Combustion Flame Synthesizing of Diamond Film and Joining on Metal Surface

利用氧气和乙炔混合气体的燃烧火焰，在金属表面合成金刚石膜。本研究的目的是将合成的金刚石薄膜与金属钼表面结合。当Mo表面温度低于1200K时，合成的金刚石脱离金属表面。低温合成的金刚石结晶为八面体结构。另一方面，当加热Mo表面温度超过1400 K时，合成的金刚石强烈地结合到金属表面。此时的金刚石的形式是几微米的球体。X射线衍射结果表明，加入金刚石的物质为三氧化钼（MoO_3）。合成的金刚石，根据红外线的吸收峰判断含有氮或空隙等杂质，分为Ia型和I B型，使用计算机模拟，计算出金刚石和与金属表面的界面中产生的热应力。从计算结果来看，MoO_3的存在确实降低了应力，同时提高了界面的结合强度。其次考察了表面光洁度的状况以及表面粗糙度对金刚石成分的影响。在金刚石膏剂抛光的Mo表面，与Al_2O_3颗粒和SiC颗粒抛光相比，金刚石的成分密度最高。这使得Mo表面粗糙度变粗，而且即使在较低的表面温度下金刚石膜也能结合。例如，在Ra=0.82 μ m的表面粗糙度中，可以通过1323K的低温使金属表面结合组合金刚石。

Using a combustion flame of oxygen and mixture gas with acetylene, it synthesized diamond film on the metal surface. It is that the purpose of this study lets the synthesized diamond film join the Mo metal surface. When temperature of Mo surface is lower than 1200K,the diamond synthesized comes off the metal surface. The crystallization of diamond synthesized by low temperature was octahedron construction. On the other hand, the diamond synthesized joins to the metal surface strongly when heats up Mo surface temperature than 1400 K.The form of diamond of this time was a sphere of several micron. The matter letting join a diamond from a result of X-ray diffraction is taken as tri-oxidized Mo (MoO_3). The diamond synthesized was classified in I a type and I b type to contain impurities such as nitrogen or voids when judged from infrared rays absorption peak.Using a computer simulation, heat stress to occur in a diamond and a boundary surface with the metal surface was calculated. From this calculation result, the existence of MoO_3 did decrease of stress, besides, the joining strength of boundary surface increase.It examined the surface finish condition and influence of the surface roughness given to diamond composition next. Mo surface of diamond paste finish, composition density of diamond is the highest when compares the surface finish by Al_2O_3 particle or SiC particle. It makes the Mo surface roughness coarse, and diamond film comes to join even the low surface temperature furthermore. For example, in the surface roughness of Ra=0.82 mum, it gets possible to let the metal surface join composition diamond by low temperature of 1323K.